Suddenly the heartbeat is very uncomfortable may be physiological factors, may also be arrhythmia. 1. Physiological factors: due to emotional excitement or nervousness, strenuous exercise and other factors will activate the sympathetic nervous system, a large amount of secretion of catecholamines, the heart rate accelerated, the amount of beat increased, resulting in a sudden heartbeat is very uncomfortable. This is a normal physiological phenomenon, patients should pay attention to deep breathing to adjust their emotions, and maintain sufficient sleep can be relieved. 2. Arrhythmia: Suddenly heartbeat is very uncomfortable may be caused by arrhythmia tachycardia, due to emotional fluctuations, quarrels and other factors may make the sympathetic nerve excitation, the body secretion of catecholamine increase, promote myocardial contraction, resulting in heart rate acceleration, triggered by arrhythmia, caused by sudden heartbeat is very uncomfortable feeling. Patients should develop good living habits, if the long time has not improved or recurrent episodes, patients need to go to the hospital in a timely manner.